U.S. patent application number 13/185450 was filed with the patent office on 2011-12-01 for multi-chamber cvd processing system.
This patent application is currently assigned to VEECO INSTRUMENTS, INC.. Invention is credited to Eric A. Armour, Ajit Paranjpe, William E. Quinn.
Application Number | 20110290175 13/185450 |
Document ID | / |
Family ID | 47558660 |
Filed Date | 2011-12-01 |
United States Patent
Application |
20110290175 |
Kind Code |
A1 |
Paranjpe; Ajit ; et
al. |
December 1, 2011 |
Multi-Chamber CVD Processing System
Abstract
A multi-chamber CVD system includes a plurality of substrate
carriers where each substrate carrier is adapted to support at
least one substrate. A plurality of enclosures are each configured
to form a deposition chamber enclosing one of the plurality of
substrate carriers to maintain an independent chemical vapor
deposition process chemistry for performing a processing step. A
transport mechanism transports each of the plurality of substrate
carriers to each of the plurality of enclosures in discrete steps
that allow processing steps to be performed in the plurality of
enclosures for a predetermined time. In some embodiments, the
substrate carrier can be rotatable.
Inventors: |
Paranjpe; Ajit; (Basking
Ridge, NJ) ; Armour; Eric A.; (Pennington, NJ)
; Quinn; William E.; (Whitehouse, NJ) |
Assignee: |
VEECO INSTRUMENTS, INC.
Plainview
NY
|
Family ID: |
47558660 |
Appl. No.: |
13/185450 |
Filed: |
July 18, 2011 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
12479834 |
Jun 7, 2009 |
|
|
|
13185450 |
|
|
|
|
Current U.S.
Class: |
117/85 ; 117/101;
117/88; 118/712; 118/719 |
Current CPC
Class: |
C23C 16/4582 20130101;
C23C 16/54 20130101; C30B 35/00 20130101; C30B 25/025 20130101 |
Class at
Publication: |
117/85 ; 117/88;
117/101; 118/712; 118/719 |
International
Class: |
C30B 25/02 20060101
C30B025/02; C30B 25/08 20060101 C30B025/08; C30B 25/12 20060101
C30B025/12 |
Claims
1. A multi-chamber CVD processing system comprising: a. a plurality
of substrate carriers, each substrate carrier adapted to support at
least one substrate; b. a plurality of enclosures, each of the
plurality of enclosures configured to form a deposition chamber
enclosing one of the plurality of substrate carriers to maintain an
independent environment for performing a processing step; and c. a
transport mechanism that transports each of the plurality of
substrate carriers to each of the plurality of enclosures in
discrete steps that allows processing steps to be performed in the
plurality of enclosures for a predetermined time.
2. The multi-chamber CVD system of claim 1 which further comprises
a plurality of heaters, each of the plurality of heaters
corresponding to each of the plurality of enclosures.
3. The multi-chamber CVD system of claim 2 wherein each of the
plurality of heaters is proximate to each of the plurality of
substrate carriers when each of the plurality of substrate carriers
is enclosed by the plurality of enclosures.
4. The multi-chamber CVD system of claim 1 wherein at least one of
the plurality of enclosures comprises a physical enclosure.
5. The multi-chamber CVD system of claim 1 wherein at least one of
the plurality of enclosures is movable relative at least one of the
plurality of substrate carriers to form at least one of the
plurality of deposition chambers.
6. The multi-chamber CVD system of claim 1 wherein at least one of
the plurality of substrate carriers is movable relative to at least
one of the plurality of enclosures to form at least one of the
plurality of deposition chambers.
7. The multi-chamber CVD system of claim 1 wherein at least one of
the plurality of enclosures and a corresponding one of the
plurality of substrate carriers are both movable to form at least
one of the plurality of deposition chambers.
8. The multi-chamber CVD system of claim 1 wherein at least one of
the plurality of enclosures comprises a gas curtain that forms at
least one boundary of the corresponding enclosure.
9. The multi-chamber CVD system of claim 1 wherein at least one of
the plurality of enclosures comprises an in-situ measurement
device.
10. The multi-chamber CVD system of claim 9 wherein the in-situ
measurement device is selected from a pyrometer, reflectometer,
deflectometer, ellipsometer, photoluminescence spectrometer,
combination pyrometer/reflectometer, a combined
deflectometer/reflectometer/temperature tool, and
electroluminescence spectrometer.
11. The multi-chamber CVD system of claim 1 wherein the transport
mechanism further comprises a plurality of heaters, each of the
plurality of heaters being proximate to each of the plurality of
substrate carriers.
12. The multi-chamber CVD system of claim 1 wherein the transport
mechanism transports each of the plurality of substrate carriers to
each of the plurality of enclosures on along a rail.
13. The multi-chamber CVD system of claim 1 wherein the transport
mechanism transports each of the plurality of substrate carriers to
each of the plurality of enclosures along a track.
14. The multi-chamber CVD system of claim 1 wherein the transport
mechanism transports each of the plurality of substrate carriers to
each of the plurality of enclosures using a conveyor.
15. The multi-chamber CVD system of claim 1 wherein the transport
mechanism transports each of the plurality of substrate carriers to
each of the plurality of enclosures in a linear path.
16. The multi-chamber CVD system of claim 1 wherein the transport
mechanism transports each of the plurality of substrate carriers to
each of the plurality of enclosures in a non-linear path.
17. The multi-chamber CVD system of claim 1 wherein the transport
mechanism transports each of the plurality of substrate carriers to
each of the plurality of enclosures in a circular path.
18. The multi-chamber CVD system of claim 1 wherein the transport
mechanism transports each of the plurality of substrate carriers to
each of the plurality of enclosures in an oval path.
19. The multi-chamber CVD system of claim 1 wherein the transport
mechanism is coupled to an automated substrate handling mechanism
that performs at least one of loading and unloading of substrates
to and from the plurality of substrate carriers.
20. The multi-chamber CVD system of claim 1 wherein at least one of
the plurality of substrate carriers is a rotatable substrate
carrier.
21. The multi-chamber CVD system of claim 1 wherein at least one of
the plurality of substrate carriers comprises a susceptor and a
substrate carrier.
22. The multi-chamber CVD system of claim 1 wherein at least one of
the plurality of substrate carriers is a susceptorless substrate
carrier.
23. The multi-chamber CVD system of claim 1 wherein at least one of
the plurality of substrate carriers is a planetary motion
carrier.
24. The multi-chamber CVD system of claim 1 which further comprises
a gas distribution injector which injects at least one precursor
gas, wherein at least one precursor gas flows through the injector
in a direction that is substantially perpendicular to the substrate
carrier.
25. The multi-chamber CVD system of claim 1 further comprising a
gas distribution injector which injects at least one precursor gas,
wherein the at least one precursor gas flows through the injector
in a direction that is substantially parallel to the substrate
carrier.
26. The multi-chamber CVD system of claim 1 further comprising a
gas distribution injector which injects at least one precursor gas,
wherein at least one precursor gas flows through the injector in a
direction that is substantially perpendicular to the substrate
carrier and wherein at least one precursor gas flows through the
injector in a direction that is substantially parallel to the
substrate carrier.
27. A multi-chamber CVD process system comprising: a. a plurality
of substrate carriers, each substrate carrier adapted to support at
least one substrate; b. a plurality of enclosures, each of the
plurality of enclosures configured to form a deposition chamber
enclosing one of the plurality of substrate carriers to maintain an
independent environment for performing a processing step; c. a
plurality of heaters that each heat a corresponding one of the
plurality of substrates to a desired process temperature for
performing the processing steps; and d. a transport mechanism that
transports each of the plurality of substrate carriers to each of
the plurality of enclosures in discrete steps that allows
processing steps to be performed in the plurality of enclosures for
a predetermined time.
28. The multi-chamber CVD system of claim 27 wherein the transport
mechanism further comprises a plurality of heaters, each of the
plurality of heaters being proximate to each substrate carrier.
29. The multi-chamber CVD system of claim 27 wherein at least one
of the plurality of heaters is positioned inside a corresponding
one of the plurality of deposition chambers proximate to the
substrate carrier.
30. The multi-chamber CVD system of claim 27 wherein at least one
of the plurality of heaters has a first portion that is positioned
inside a corresponding one of the plurality of deposition chambers
proximate to the substrate carrier and a second portion that is
positioned outside of the corresponding one of the plurality of
deposition chambers.
31. The multi-chamber CVD system of claim 27 wherein the transport
mechanism transports at least one of the plurality of heaters along
with a corresponding one of the plurality of substrate
carriers.
32. The multi-chamber CVD system of claim 27 wherein each of the
plurality of heaters comprises a first and second section that
define a gap for passing the plurality of substrate carriers.
33. The multi-chamber CVD system of claim 27 wherein at least one
of the plurality of heaters comprises a resistive heater.
34. The multi-chamber CVD system of claim 27 wherein at least one
of the plurality of heaters comprises an RF heater.
35. The multi-chamber CVD system of claim 27 wherein at least one
of the plurality of substrate carriers is a rotatable substrate
carrier.
36. The multi-chamber CVD system of claim 27 wherein at least one
of the plurality of substrate carriers comprises a susceptor and a
substrate carrier.
37. The multi-chamber CVD system of claim 27 wherein at least one
of the plurality of substrate carriers is a susceptorless substrate
carrier.
38. The multi-chamber CVD system of claim 27 wherein at least one
of the plurality of substrate carriers is a planetary motion
carrier.
39. The multi-chamber CVD system of claim 27 wherein at least one
of the plurality of enclosures comprises an in-situ measurement
device.
40. The multi-chamber CVD system of claim 39 wherein the in-situ
measurement device is selected from a pyrometer, reflectometer,
deflectometer, ellipsometer, photoluminescence spectrometer,
combination pyrometer/reflectometer, a combined
deflectometer/reflectometer/temperature tool, and
electroluminescence spectrometer.
41. The multi-chamber CVD system of claim 27 wherein the transport
mechanism transports each of the plurality of substrate carriers to
each of the plurality of enclosures using one of a track, a
conveyor, a rail, a tank tread, or any combination thereof
42. The multi-chamber CVD system of claim 27 wherein the transport
mechanism transports each of the plurality of substrate carriers to
each of the plurality of enclosures in a linear path.
43. The multi-chamber CVD system of claim 27 wherein the transport
mechanism transports each of the plurality of substrate carriers to
each of the plurality of enclosures in a non-linear path.
44. The multi-chamber CVD system of claim 27 wherein the transport
mechanism is coupled to an automated substrate handling mechanism
that performs at least one of loading and unloading of substrates
to and from the plurality of substrate carriers.
45. The multi-chamber CVD system of claim 27 further comprising a
gas distribution injector which injects at least one precursor gas,
wherein the at least one precursor gas flows through the injector
in a direction that is substantially perpendicular to the substrate
carrier.
46. The multi-chamber CVD system of claim 27 further comprising a
gas distribution injector which injects at least one precursor gas,
wherein the at least one precursor gas flows through the injector
in a direction that is substantially parallel to the substrate
carrier.
47. The multi-chamber CVD system of claim 27 further comprising a
gas distribution injector which injects at least one precursor gas,
wherein at least one precursor gas flows through the injector in a
direction that is substantially perpendicular to the substrate
carrier and wherein at least one precursor gas flows through the
injector in a direction that is substantially parallel to the
substrate carrier.
48. A method of forming multiple epitaxial layers on a substrate
using a multi-chamber chemical vapor deposition system, the method
comprising: a. enclosing a first substrate carrier comprising at
least one substrate at a first location to form a first deposition
chamber that maintains a first independent environment; b. growing
a first epitaxial layer on the at least one substrate in the first
deposition chamber at the first location with the first independent
environment; c. transporting the first substrate carrier after the
first epitaxial layer is grown to a second location and enclosing
the first substrate carrier to form a second deposition chamber
that maintains a second independent environment; and d. growing a
second epitaxial layer on top of the first epitaxial layer in the
second deposition chamber at the second location with the second
independent environment.
49. The method of claim 48 further comprising: a. enclosing a
second substrate carrier comprising at least one substrate at the
first location to form the first deposition chamber that maintains
the first independent environment; and b. growing the first
epitaxial layer on the at least one substrate on the second
substrate carrier in the first deposition chamber at the first
location with the first independent environment.
50. The method of claim 49 wherein the at least one substrate on
the first and the second substrate carriers are processed
simultaneously in time.
51. The method of claim 48 wherein the enclosing the first
substrate carrier to form the first and the second deposition
chambers comprises moving a chamber over the first substrate
carrier to isolate a respective one of the first and second
chemical vapor deposition process chemistry inside the first and
the second deposition chambers.
52. The method of claim 48 wherein the enclosing the first
substrate carrier to form the first and the second deposition
chambers comprises moving the first substrate carrier into a
chamber to isolate a respective one of the first and second
environment inside the first and the second deposition
chambers.
53. The method of claim 48 wherein the enclosing the first
substrate carrier to form the first and the second deposition
chambers comprising forming gas curtains to isolate a respective
one of the first and second environment.
54. The method of claim 48 wherein at least one of the first and
the second independent chemical vapor deposition process
chemistries is established using a heater that is fixed inside a
corresponding one of the first and second process chambers.
55. The method of claim 48 wherein at least one of the first and
the second environments is established using a heater that is fixed
to a corresponding one of the first and second substrate carrier so
that it moves with the corresponding one of the first and second
substrate carrier.
56. The method of claim 48 wherein the transporting of the first
substrate carrier to a second location comprises transporting the
first substrate carrier along at least one of a track, rail, or
conveyor, or any combination thereof
57. The method claim 48 wherein the transporting of the first
substrate carrier to a second location comprises transporting the
first substrate carrier along a linear path.
58. The method claim 48 wherein the transporting of the first
substrate carrier to a second location comprises transporting the
first substrate carrier along a non-linear path.
59. The method of claim 48 further comprising translating the first
substrate carrier.
60. The method of claim 48 further comprises performing an in-situ
measurement while growing at least one of the first and second
epitaxial layers.
61. The method of claim 60 wherein the in-situ measurement is
performed using a device selected from a pyrometer, reflectometer,
deflectometer, ellipsometer, photoluminescence spectrometer,
combination pyrometer/reflectometer, a combined
deflectometer/reflectometer/temperature tool, and
electroluminescence spectrometer.
62. The method of claim 48 wherein at least one of the plurality of
substrate carriers is a rotatable substrate carrier.
63. The method of claim 48 wherein at least one of the plurality of
substrate carriers comprises a susceptor and a substrate
carrier.
64. The method of claim 48 wherein at least one of the plurality of
substrate carriers is a susceptorless substrate carrier.
65. The method of claim 48 wherein at least one of the plurality of
substrate carriers is a planetary motion carrier.
66. The method of claim 48 further comprising gas distribution
injection of at least one precursor gas, wherein the at least one
precursor gas is injected in a direction that is substantially
perpendicular to the substrate carrier.
67. The method of claim 48 further comprising gas distribution
injection of at least one precursor gas, wherein the at least one
precursor gas is injected in a direction that is substantially
parallel to the substrate carrier.
68. The method of claim 48 further comprising gas distribution
injection of at least one precursor gas, wherein at least one
precursor gas is injected in a direction that is substantially
perpendicular to the substrate carrier and wherein at least one
precursor gas is injected in a direction that is substantially
parallel to the substrate carrier.
69. A multi-chamber chemical vapor deposition system comprising: a.
a means for enclosing a plurality of substrate carriers which
support at least one substrate at a plurality of fixed locations to
form a plurality of deposition chambers that each maintain an
independent environment; b. a means for growing an epitaxial layer
on the at least one substrate supported by the plurality of
substrate carriers in the plurality of deposition chambers that are
each maintaining the independent environment; and c. a means for
transporting the plurality of substrate carriers between the
plurality of deposition chambers in discrete steps.
70. The multi-chamber chemical vapor deposition system of claim 69
which further comprises means for rotating at least one of the
plurality of substrate carriers.
Description
RELATED APPLICATION SECTION
[0001] This application is a continuation-in-part of U.S. patent
application Ser. No. 12/479,834, filed Jun. 7, 2009, entitled
"Continuous Feed Chemical Vapor Deposition System." The entire
specification of U.S. patent application Ser. No. 12/479,834 is
incorporated herein by reference.
[0002] The section headings used herein are for organizational
purposes only and should not to be construed as limiting the
subject matter described in the present application in any way.
INTRODUCTION
[0003] Chemical vapor deposition (CVD) involves directing one or
more gases containing chemical species onto a surface of a
substrate so that the reactive species react and form a film on the
surface of the substrate. For example, CVD can be used to grow
compound semiconductor material on a crystalline semiconductor
substrate. Compound semiconductors, such as III-V semiconductors,
are commonly formed by growing various layers of semiconductor
materials on a substrate using a source of a Group III metal and a
source of a Group V element. In one CVD process, sometimes referred
to as a chloride process, the Group III metal is provided as a
volatile halide of the metal, which is most commonly a chloride,
such as GaCl.sub.2, and the Group V element is provided as a
hydride of the Group V element.
[0004] Another type of CVD is metal organic chemical vapor
deposition (MOCVD). MOCVD uses chemical species that include one or
more metal organic compounds, such as alkyls of the Group III
metals, such as gallium, indium, and aluminum. MOCVD also uses
chemical species that include hydrides of one or more of the Group
V elements, such as NH.sub.3, AsH.sub.3, PH.sub.3 and hydrides of
antimony. In these processes, the gases are reacted with one
another at the surface of a substrate, such as a substrate of
sapphire, Si, SiC, SiGe, AlSiC, GaAs, InP, InAs or GaP, to form a
III-V compound of the general formula
In.sub.xGa.sub.YAl.sub.ZN.sub.AAs.sub.BP.sub.CSb.sub.D, where X+Y+Z
equals approximately one, and A+B+C+D equals approximately one, and
each of X, Y, Z, A, B, and C can be between zero and one. In some
instances, bismuth may be used in place of some or all of the other
Group III metals. Many compound semiconductors, such as GaAs, GaN,
GaAlAs, InGaAsSb, InP, AsP, ZnSe, ZnTe, HgCdTe, InAsSbP, InGaN,
AlGaN, SiGe, SiC, ZnO and InGaAlP, have been grown by MOCVD.
[0005] Another type of CVD is known as Halide Vapor Phase Epitaxy
(HVPE). In one HVPE process, Group III nitrides (e.g., GaN, AN) are
formed by reacting hot gaseous metal chlorides (e.g., GaCl or AlCl)
with ammonia gas (NH.sub.3). The metal chlorides are generated by
passing hot HCl gas over the hot Group III metals. All reactions
are done in a temperature controlled quartz furnace. One feature of
HVPE is that it can have a very high growth rate, up to 100 .mu.m
per hour for some state-of-the-art processes. Another feature of
HVPE is that it can be used to deposit relatively high quality
films because films are grown in a carbon-free environment and
because the hot HCl gas provides a self-cleaning effect.
SUMMARY OF THE INVENTION
[0006] The present teaching relates to a multi-chamber CVD
processing system which comprises a plurality of substrate
carriers, each substrate carrier adapted to support at least one
substrate; a plurality of enclosures, each of the plurality of
enclosures configured to form a deposition chamber enclosing one of
the plurality of substrate carriers to maintain an independent
environment for performing a processing step; and a transport
mechanism that transports each of the plurality of substrate
carriers to each of the plurality of enclosures in discrete steps
that allows processing steps to be performed in the plurality of
enclosures for a predetermined time. The multi-chamber CVD system
can additionally comprise a plurality of heaters, each of the
plurality of heaters corresponding to each of the plurality of
enclosures. The multi-chamber CVD system can additionally comprise
an in-situ measurement device placed in at least one of the
plurality of enclosures. The transport mechanism can additionally
comprise a plurality of heaters, each of the plurality of heaters
being proximate to each of the plurality of substrate carriers. The
transport mechanism can transport each of the plurality of
substrate carriers in a linear or non-linear path using, for
example, a rail, track or conveyor system, which can also include
belts, push-rods, and magnetically coupled drives, such as magnetic
linear motors. In some embodiments, at least one of the plurality
of substrate carriers in the multi-chamber CVD system is a
rotatable.
[0007] The present teaching also relates to a multi-chamber CVD
process system which comprises a plurality of substrate carriers,
where each substrate carrier is adapted to support at least one
substrate; a plurality of enclosures, each of the plurality of
enclosures configured to form a deposition chamber enclosing one of
the plurality of substrate carriers to maintain an independent
environment for performing a processing step; a plurality of
heaters that each heat a corresponding one of the plurality of
substrates to a desired process temperature for performing the
processing steps; and a transport mechanism that transports each of
the plurality of substrate carriers to each of the plurality of
enclosures in discrete steps that allows processing steps to be
performed in the plurality of enclosures for a predetermined time.
The transport mechanism can additionally comprise a plurality of
heaters which are proximate to each susceptor. The heaters can be
positioned inside the deposition chamber or correspondingly
translated with the substrate carrier. In some embodiments, at
least one of the plurality of substrate carriers in the
multi-chamber CVD system is a rotatable.
[0008] The present teaching also relates to a method of forming
multiple epitaxial layers on a substrate using a multi-chamber
chemical vapor deposition system where the method comprises
enclosing a first substrate carrier comprising at least one
substrate at a first location to form a first deposition chamber
that maintains a first independent environment; growing a first
epitaxial layer on the at least one substrate in the first
deposition chamber at the first location with the first independent
environment; transporting the first substrate carrier after the
first epitaxial layer is grown to a second location and enclosing
the first substrate carrier to form a second deposition chamber
that maintains a second independent environment; and growing a
second epitaxial layer on top of the first epitaxial layer in the
second deposition chamber at the second location with the second
independent environment. The method can further comprise enclosing
a second substrate carrier comprising at least one substrate at the
first location to form the first deposition chamber that maintains
the first independent environment; and growing the first epitaxial
layer on the at least one substrate on the second substrate carrier
in the first deposition chamber at the first location with the
first independent environment.
[0009] The present teaching also relates to a multi-chamber
chemical vapor deposition system which comprises a means for
enclosing a plurality of substrate carriers which support at least
one substrate at a plurality of fixed locations to form a plurality
of deposition chambers that each maintain an independent
environment; a means for growing an epitaxial layer on the at least
one substrate supported by the plurality of substrate carriers in
the plurality of deposition chambers that are each maintaining the
independent environment; and a means for transporting the plurality
of substrate carriers between the plurality of deposition chambers
in discrete steps. In some embodiments, at least one of the
plurality of substrate carriers in the multi-chamber chemical vapor
deposition system is a rotatable.
[0010] Within the CVD processing systems described herein, the
substrate carriers can comprise, for example, a susceptor and
substrate carrier assembly, a susceptorless carrier, or a planetary
carrier.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] The present teaching, in accordance with preferred and
exemplary embodiments, together with further advantages thereof, is
more particularly described in the following detailed description,
taken in conjunction with the accompanying drawings. The skilled
person in the art will understand that the drawings, described
below, are for illustration purposes only. The drawings are not
necessarily to scale, emphasis instead generally being placed upon
illustrating principles of the teaching. The drawings are not
intended to limit the scope of the Applicant's teaching in any
way.
[0012] FIG. 1 illustrates a side-view of one embodiment of a
multi-chamber CVD system according to the present teaching
[0013] FIG. 2A illustrates a side-view of one embodiment of a
deposition chamber according to the present teaching where the
deposition chamber is formed by moving an enclosure over a
substrate carrier.
[0014] FIG. 2B illustrates a side-view of one embodiment of a
deposition chamber according to the present teaching where the
deposition chamber is formed by moving a substrate carrier into an
enclosure.
[0015] FIG. 3A, FIG. 3B, FIG. 3C, and FIG. 3D show examples of
different embodiments of the heaters useful in the present
system.
[0016] FIG. 4 illustrates a side-view of the embodiment of the
multi-chamber CVD system in FIG. 1 in a particular mode.
[0017] FIG. 5 illustrates a side-view of the embodiment of the
multi-chamber CVD system in FIG. 1 in another particular mode.
[0018] FIG. 6 illustrates a side-view of an embodiment of the
multi-chamber CVD system according to the present teaching in
another particular mode.
[0019] FIG. 7A illustrates a side-view of one embodiment of a
deposition chamber according to the present teaching where process
gases are injected horizontally into the deposition chamber.
[0020] FIG. 7B illustrates a top-down view (in the A direction) of
the deposition chamber shown in FIG. 7A.
[0021] FIG. 8 illustrates a perspective top-view of another
variation of a horizontal flow gas injector CVD system according to
the present teaching.
[0022] FIG. 9 illustrates a side-view of another variation of a
horizontal flow gas injector CVD system according to the present
teaching.
DESCRIPTION OF VARIOUS EMBODIMENTS
[0023] Reference in the specification to "one embodiment" or "an
embodiment" means that a particular feature, structure, or
characteristic described in connection with the embodiment is
included in at least one embodiment of the teaching. The
appearances of the phrase "in one embodiment" in various places in
the specification are not necessarily all referring to the same
embodiment.
[0024] It should be understood that the individual steps of the
methods of the present teachings may be performed in any order
and/or simultaneously as long as the teaching remains operable.
Furthermore, it should be understood that the apparatus and methods
of the present teachings can include any number or all of the
described embodiments as long as the teaching remains operable.
[0025] The present teaching will now be described in more detail
with reference to exemplary embodiments thereof as shown in the
accompanying drawings. While the present teaching is described in
conjunction with various embodiments and examples, it is not
intended that the present teaching be limited to such embodiments.
On the contrary, the present teaching encompasses various
alternatives, modifications and equivalents, as will be appreciated
by those of skill in the art. Those of ordinary skill in the art
having access to the teaching herein will recognize additional
implementations, modifications, and embodiments, as well as other
fields of use, which are within the scope of the present disclosure
as described herein.
[0026] The present teaching relates to methods and apparatus for
reactive gas phase processing, such as CVD, MOCVD, and HYPE. In
reactive gas phase processing of semiconductors materials,
semiconductor substrates or substrates are mounted in a substrate
carrier inside a reaction chamber. A gas distribution injector or
injector head is mounted facing towards the substrate carrier. The
injector or injector head typically includes a plurality of gas
inlets that receive a combination of gases. The injector or
injector head provides the combination of gasses to the reaction
chamber for chemical vapor deposition. Many gas distribution
injectors have showerhead devices spaced in a pattern on the head.
The gas distribution injectors direct the precursor gases at the
substrate carrier in such a way that the precursor gases react as
close to the substrates as possible, thus maximizing reaction
processes and epitaxial growth at the substrate surface.
[0027] Some gas distribution injectors provide a shroud that
assists in providing a laminar gas flow during the chemical vapor
deposition process. Also, one or more carrier gases can be used to
assist in providing a laminar gas flow during the chemical vapor
deposition process. The carrier gas typically does not react with
any of the process gases and does not otherwise affect the chemical
vapor deposition process. A gas distribution injector typically
directs the precursor gases from gas inlets of the injector to
certain targeted regions of the reaction chamber where substrates
are processed.
[0028] For example, in MOCVD processes, the injector introduces
combinations of precursor gases including metal organics and
hydrides, such as ammonia or arsine into a reaction chamber through
the injector. A carrier gas, such as hydrogen, nitrogen, or inert
gases, such as argon or helium, is often introduced into the
reactor through the injector to aid in maintaining laminar flow at
the substrate carrier. The precursor gases mix in the reaction
chamber and react to form a film on a substrate. Many compound
semiconductors, such as GaAs, GaN, GaAlAs, InGaAsSb, InP, ZnSe,
ZnTe, HgCdTe, InAsSbP, InGaN, AlGaN, SiGe, SiC, ZnO and InGaAlP,
have been grown by MOCVD.
[0029] In both MOCVD and HVPE processes, the substrate is
maintained at an elevated temperature within a reaction chamber.
The process gases are typically maintained at a relatively low
temperature of about 50-60.degree. C. or below, when they are
introduced into the reaction chamber. As the gases reach the hot
substrate, their temperature, and hence their available energy for
reaction, increases.
[0030] The most common type of CVD reactor is a rotating disc
reactor. Such a reactor typically uses a disc-like substrate
carrier. The substrate carrier has pockets or other features
arranged to hold one or more substrates to be treated. The carrier,
with the substrates positioned thereon, is placed into a reaction
chamber and held with the substrate-bearing surface of the carrier
facing in an upstream direction. The carrier is rotated, typically
at rotational velocities of several hundred revolutions per minute,
about an axis extending in the upstream to downstream direction.
The rotation of the substrate carrier improves uniformity of the
deposited semiconductor material. The substrate carrier is
maintained at a desired elevated temperature, which can be in the
range of about 350.degree. C. to about 1,600.degree. C. during this
process.
[0031] While the carrier is rotated about the axis, the reaction
gases are introduced into the chamber from a flow inlet element
above the carrier. The flowing gases pass downwardly toward the
carrier and substrates, preferably in a laminar plug flow. As the
gases approach the rotating carrier, viscous drag impels them into
rotation around the axis so that in a boundary region near the
surface of the carrier, the gases flow around the axis and
outwardly toward the periphery of the carrier. As the gases flow
over the outer edge of the carrier, they flow downwardly toward
exhaust ports positioned below the carrier. Most commonly, MOCVD
processes are performed with a succession of different gas
compositions and, in some cases, different substrate temperatures,
to deposit a plurality of layers of semiconductor having differing
compositions as required to form a desired semiconductor
device.
[0032] Other types of CVD or MOCVD reactors include disk-like
substrate carriers which do not rotate in the reactor during
deposition and/or epitaxial layer growth.
[0033] The apparatus and methods of the present teaching relate to
linear and in-line CVD processing system. The term "in-line" as
used herein in connection with the transport of substrates refers
to the transport of substrates in a plane from one chamber of a
multi-chamber CVD system to another chamber of a multi-chamber CVD
system. The transporting in-line is not necessary transporting in a
straight line. The transporting can be linear or can be along a
curve. For example, commercially available in-line systems have
been arranged in several parallel lines, in a circle, in a U-shaped
arrangement, or vertically stacked in a linear or U-shaped
arrangement. Furthermore, the transporting can be along a closed
rail or track with the same starting and ending point or can be in
only one direction only. The term "in line" when referring to
transport mechanisms according to the present teaching can include
a conveyor-type transport mechanism, such as a conveyor belt that
includes two or more rollers with a continuous belt that rotates
about them. Other types of system processing architectures useful
in the present invention include those found in U.S. Provisional
Patent Application Ser. No. 61/237,141, filed Aug. 26, 2009,
entitled "System for Fabricating a Pattern on Magnetic Recording
Media", the contents of which are hereby incorporated herein by
reference.
[0034] Known apparatus and methods for CVD, such as MOCVD and HYPE,
are not suitable for linear and in-line processing systems. The
apparatus and methods of the present teaching can perform any type
of CVD, such as MOCVD and HYPE. In one aspect of the present
teaching, the apparatus and methods of the present teaching use an
in-line discontinuous transport mechanism. The term "discontinuous
transport mechanism" as referred to herein is a transport mechanism
that transports substrates and/or substrate carriers in
discontinuous steps. That is, the substrates and/or the substrate
carries are transported from one CVD processing chamber in the
multi-chamber CVD processing system to another CVD processing
chamber in the multi-chamber CVD processing system and then the
substrates and/or substrate carriers are positioned in their
respective CVD process chamber at fixed location for a
predetermined time while a CVD process step is performed.
[0035] FIG. 1 illustrates a side-view of one embodiment of a
multi-chamber CVD system 100 according to the present teaching. The
CVD system 100 includes a substrate loading station 102, such as
the automated mechanical handling system that is manufactured by
Veeco Instruments Inc. of Plainview, NY. The substrate loading
station 102 typically opens to atmospheric pressure where
substrates are inserted for CVD processing. A gate valve interfaces
the substrate loading station 102 to an input of the substrate
transport mechanism 104 located in a housing 106 containing a
plurality of enclosures 108 that form deposition chambers 110 and
152 in the multi-chamber CVD system 100. At the top of deposition
chambers 110 and 152 is gas flow flange 300. Gas flow flange 300 is
a flow inlet element typically found in MOCVD or CVD process
chambers. Such gas flow flanges typically have at least one
reactive gas source, and in some instances a carrier gas, as well
as manifolds and baffles and gas distribution chambers to ensure
proper gas flow towards the direction of the substrate. An example
of a suitable gas flow flange can be found in U.S. Patent
Publication No. 2010/0143588. At the bottom of deposition chambers
110 and 152 is an orifice 160 which can be outfitted with
appropriate pumps, gas sources, and exhaust manifolds so as to
pressurize or evacuate deposition chambers 110 and 152, depending
upon the process conditions or if deposition chambers 110 and 152
are to be purged of reactive gases so that the enclosures 108 can
be moved into recess 170 and the spindles 140A and 140B translate
to its next stop within system 100. Spindles 140A and 140B can be
connected to the substrate transport system 104 by a variety of
connectors known to those skilled in the art, such as, for example
and not limited to , mechanical connectors (for example, nut and
bolt), electro-mechanical (for example, solenoid pin), and magnetic
couplings. Other substrate transport systems and spindles described
herein can be connected in a similar fashion.
[0036] The processed substrates are removed from the multi-chamber
CVD system 100 with a substrate unloading station 112 positioned at
the end of the housing 106 containing the plurality of enclosures
108. The substrate unloading station 112 can also be the automated
mechanical handling system that is manufactured by Veeco
Instruments Inc. of Plainview, NY. The substrate unloading station
112 typically opens to atmospheric pressure where substrates are
removed after CVD processing. A gate valve interfaces the substrate
unloading station 112 to the output of the substrate transport
mechanism 104 located in the housing 106 containing the plurality
of enclosures 108 that form deposition chambers 110 and 152 in the
multi-chamber CVD system 100. Both the substrate loading station
102 and the substrate unloading station 112 can also be pump-purged
independently from the rest of the system.
[0037] There are a plurality of substrate carriers 114A and 114B,
which are movable along the transport mechanism 104. The
multi-chamber CVD system shown in FIG. 1 illustrates only two
substrate carriers to simply the figure. In practice, a
multi-chamber CVD system according to the present teaching will
include numerous substrate carriers 114A and 114B that are enclosed
in enclosures 108 to form numerous deposition chambers 110 and 152.
Some CVD systems are configured to have one deposition chamber for
each layer grown on the substrate.
[0038] The plurality of substrate carriers 114A and 114B interface
with the substrate loading station 102 so that substrates can be
transferred from the substrate loading station 102 to the adjacent
substrate carriers 114A and 114B. Each of the plurality of
substrate carriers 114A and 114B includes a susceptor 116A and
116B, respectively, and substrate carrier assembly 118A and 118B,
respectively. The susceptor 116A and 116B includes a base structure
made of a material having high thermal conductivity at high
temperature so that thermal energy is easily transferred from
heaters 122A and 122B to the substrates. The substrate carrier
assembly 118A and 118B includes a platen for holding at least one
substrate, such as a semiconductor wafer, during growth of
epitaxial layers with CVD and a spindles 140A and 140B which
supports the susceptor 116A and 116B and in some instances as
disclosed herein, heaters 122A and 122B by using heater supports
142A and 142B, which can be, for example, a single support pole or
which can be a sleeve around spindles 140A and 140B. In other
embodiments, a susceptorless wafer carrier can be used in place of
susceptor 116A and 116B and platen, where heat is transferred from
heaters 122A and 122B directly to the bottom of the wafer carrier,
which is made a material having high thermal conductivity at high
temperature so that thermal energy is easily transferred from
heaters 122A and 122B to the substrates. One type of susceptorless
wafer carrier is described in U.S. Pat. No. 6,685,774. In many
embodiments, each of the plurality of substrate carriers 114A and
114B comprises a platen that supports a plurality of substrates
which are simultaneously processed.
[0039] The multi-chamber CVD system according to the present
teaching includes a plurality of heaters 122A and 122B for
controlling the temperature at the growth surfaces of substrates
positioned in each of the plurality of deposition chambers 110 and
152 to maintain a desired growth temperature. One of the plurality
of heaters 122A and 122B is positioned in thermal contact with each
of the plurality of substrate carriers 114A and 114B. There are
many possible types of heaters that can be used to control the
temperature at the growth surface of each of the plurality of
deposition chambers 110 and 152. Heaters 122A and 122B can be
positioned inside and/or outside of the enclosures 108.
[0040] For example, the plurality of heaters 122A and 122B can be
resistive-type heaters, such as graphite heaters. Such heaters will
typically be placed inside of the deposition chambers 110 and 152
proximate to and in thermal contract with each of the plurality of
substrate carriers 114A and 114B. In one specific embodiment, three
banks of linear resistive heaters are arranged in two halves with a
gap between the two halves for passing the spindles supporting the
plurality of substrate carriers 114A and 114B. In addition, the
plurality of heaters 122A and 122B can be RF heaters that transfer
RF energy to the growth surface of each of the substrates in the
plurality of deposition chambers 110 and 152. Such heaters have RF
induction coils positioned inside or outside of the enclosures 108.
Radiant energy from lamps, for example, quartz lamps, may also be
used for heating or fine tuning of the temperature profile.
[0041] Some multi-chamber CVD systems according to the present
teaching include stationary resistive heater elements that are
shaped to define a gap or passage for the plurality of substrate
carrier 114A and 114B to be transported into and out of the
plurality of enclosures 108. For example, in one specific
embodiment, stationary resistive heaters are formed to define two
semi-circular heater elements that define a passage for the
plurality of enclosures 108 to pass into and out of the plurality
of deposition chambers 110 and 152. The passage is wide enough so
that spindles supporting the plurality of substrate carriers 114A
and 114B pass freely through the passage between the two
semi-circular heater elements when the plurality of substrate
carriers are being transported with the transport mechanism
104.
[0042] Other multi-chamber CVD systems according to the present
teaching include a first heater that includes stationary resistive
heater elements shaped to define a gap or passage for the plurality
of substrate carrier 114A and 114B to be transported into and out
of the plurality of enclosures 108 and a second heater that is
attached to the substrate carriers 114A and 114B. These heaters can
be independently controllable. The heater that is attached to the
substrate carriers 114A and 114B can be used to heat the substrates
or to maintain a desired temperature of the substrates while they
are being transported to the next deposition chamber. Using two
heaters can increase the throughput by reducing the time that it
takes the substrates to achieve the desired process
temperature.
[0043] FIG. 3A shows an example (top view) of a heater 122 which
has a gap between two halves through which the spindle can pass.
Heater element 130A and heater element 130B are connected to any
non-moving surface within chambers 110 and 152 by brackets 160A
& 162A and 160B & 162B, respectively. Appropriate wiring
and other heater controls also pass through the appropriate
brackets. Gap 170 is sufficiently wide enough to allow spindles
140A and 140B to move through as it translates through the
different chambers within the system.
[0044] FIG. 3B and FIG. 3C show examples of a heater 122 which can
be connected to spindle 140 using heater support 142 (not shown).
In FIG. 3B, supports 147 and 148 connect heater 122 to another
support (not shown). Appropriate wiring and other controls can also
flow through the supports 147 and 148. In FIG. 3C, bracket 146
connects heater 122 to a heater support (not shown) with
appropriate wiring and other controls passing through heater
support 142 (not shown) to bracket 146.
[0045] FIG. 3D shows another example (top view) of a heater 190
which has a gap between two halves through which the spindle can
pass. Heater element 196A and heater element 196B are connected to
any non-moving surface within chambers 110 and 152 by brackets 192A
& 194A and 192B & 194B, respectively. Appropriate wiring
and other heater controls also pass through the corresponding
brackets. Gap 170 is sufficiently wide enough to allow spindles
140A and 140B to move through as it translates through the
different chambers within the system.
[0046] In another embodiment, the substrates themselves are used as
a resistive heater. In this embodiment, the substrates are
constructed of a material and with a thickness that results in a
resistivity which is suitable for resistive heating. A power supply
is electrically connected to the substrates. The current generated
by the power supply is regulated so that the substrates are heated
to the desired processing temperature. One skilled in the art will
appreciate that other types of heaters can be used to heat the
substrates 104. In addition, the multi-chamber CVD system according
to the present teaching can include multiple types of heaters that
can be positioned inside and/or outside of the deposition chambers
110 and 152 to heat the growth surfaces of the substrates to the
desired processing temperatures.
[0047] In some embodiments of the present teaching, at least one of
the plurality of substrate carriers 114A and 114B rotates the at
least one substrate about an axis during processing. The rotation
rate depends upon the specific process. For some processes, the
rotation rate is up to 1,500 rpms. In other embodiments, at least
one of the plurality of substrate carriers 114A and 114B translates
the at least one substrate during processing. In yet other
embodiments, at least one of the plurality of substrate carriers
114A and 114B rotates and translates the at least one substrate
during processing. The substrate carriers could also remain
stationary or translate linearly while one or more substrates are
loaded on a planet that rotates about its axis. The substrate
carrier may be round with substrates or planets arranged in various
configurations on the carrier, or could be rectangular or square in
cases where the carrier is not rotating. The carrier configuration
is optimized for the substrate size being processed. In this
manner, substrates that are round, square or rectangular and range
in size from 2'' to 12'' typically may be processed by using the
appropriately sized and configured carrier.
[0048] The plurality of enclosures 108 are each configured to form
one of a plurality of deposition chambers 110 and 152 that enclose
one of the plurality of substrate carriers 114A and 114B in order
to maintain an independent environment. In the independent
environment, the chemical vapor deposition process chemistry can be
performed as a CVD processing step. In other instances in the
independent environment, annealing or other non-chemical vapor
deposition process chemistry steps can be performed. In some
systems according to the present teaching, each of the plurality of
deposition chambers 110 and 152 is designed and operated to perform
one of a plurality of processing steps in a sequence of CVD
processing steps. In other systems according to the present
teaching, each of the plurality of deposition chambers 110 and 152
performs one or more processing steps, which may or may not be
chemical vapor deposition process chemistry related.
[0049] In many embodiments, one or more of the plurality of
enclosures 108 comprises a physical enclosure, such as a stainless
steel enclosure or a glass bell jar. One skilled in the art will
appreciate that numerous types of materials can be used to form the
physical enclosures. In many embodiments, each of the plurality of
enclosures 108 is fluid cooled to remove the heat generated during
deposition. Conduits for water or other types of fluid cooling can
be formed in or around the plurality of enclosures 108.
[0050] In other embodiments, at least one of the plurality of
enclosures 108 comprises a gas curtain (or purge) which forms at
least one boundary of the corresponding enclosure. In these
embodiments, adjacent gas curtains can be separated by a region
that is under vacuum. The regions under vacuum remove process
gasses between adjacent deposition chambers 110 and 152 so that
separate process chemistries are maintained in each of the
plurality of deposition chambers 110 and 152. The gas curtain
(purge) can be H.sub.2, N.sub.2, NH.sub.3 and/or any combination of
them for typical GaN-type reactors. For other Group III/V type
reactors, gases such as hydrides (for example, AsH.sub.3 or
PH.sub.3) are useful. In order to reduce process cross-talk between
enclosures, the pressure within the enclosure is equilibrated to
the pressure of the overall chamber before the enclosure is opened.
Also gases may continue to flow through selected injectors located
within each injector to maintain the gas ambient necessary to
prevent untoward degradation of the substrate while the carrier is
being transferred from one station to another station.
[0051] In other embodiments, one or more gas curtains are used
between at least two of the plurality of enclosures 108. Such gas
curtains can be used to prevent process gases used in one
deposition chamber from entering into another deposition chamber so
that separate process chemistries are maintained in each of the
plurality of deposition chambers 110 and 152. In yet other
embodiments, a gas purge can be used in areas between at least two
of the plurality of deposition chambers 110 and 152. The gas purge
can be used to remove residual process gasses from the substrates
as they move through the gas purge to the next deposition
chamber.
[0052] The enclosures could operate synchronously or asynchronously
depending on the mode of operation. In a cascaded mode, a carrier
can be moved into the last station after the carrier from the last
station is removed and the process ripples through the stations. In
another mode, all the carriers move synchronously from one station
to the next. In yet another mode, the last station is unloaded, and
then the remaining carriers index synchronously to the next
station. Other operating modes are also possible in which carriers
move bi-directionally between chambers, so that one set of
contiguous chambers is used to complete one part of the growth,
while another set is used to complete another part of the growth.
The optimal operating mode is process and throughput dependent.
[0053] Each of the plurality of enclosures includes at least one
gas input port that is coupled to at least one CVD process gas
source so that the at least one gas input port injects at least one
process gas into a respective deposition chambers 110 and 152. Gas
flow flange 300 (FIGS. 2A and 2B) can include multiple gas input
ports, including elevated temperature gas input ports, that can be
used to inject CVD process gasses at temperatures above 75.degree.
C., that can be used with the multi-chamber CVD system according to
the present teaching. The walls of the deposition chambers 110 and
152 can be heated to temperatures at or above the gas input port
temperatures. The use of an elevated gas input port temperature
allows the use of a relatively low substrate carrier rotation rate,
a relatively high operating pressure, a relatively low flow rate,
or some combination of desirable substrate carrier rotation rate,
operating pressure, and gas flow rate. A different configuration of
flow flange may be used within each enclosure. For example, these
can include flow flanges configured for rotating disk reactors,
close coupled showerhead reactors, cross flow planetary reactors,
spatial or time modulated atomic layer epitaxy reactors, plasma or
hot wire CVD reactors. In general, any reactor type that is
compatible with an in-line implementation can be used. This allows
a mix and match strategy in which the best suited reactor
configuration is used for a particular growth step. Other types of
reactor designs and substrate carrier designs that are useful in
the present invention include those found in U.S. Provisional
Patent Application Ser. No. 61/472,925 filed Apr. 7, 2011, entitled
"Metal-Organic Vapor Phase Epitaxy System and Process", the
contents of which are hereby incorporated herein by reference.
[0054] The CVD process gasses can be located proximate to the
multi-chamber CVD system 100 or can be located in a remote
location. In many embodiments, a plurality of CVD gas sources, such
as MOCVD gas sources, is available to be connected to the gas input
ports of each of the plurality of deposition chambers 110 and 152
through a gas distribution manifold. The multi-chamber deposition
system 100 can be easily configured to change the material
structure being deposited by configuring the gas distribution
manifold. The gas distribution manifold can be configured manually
at the manifold or can be configured remotely by activating
electrically operated valves and solenoids. Such an apparatus is
well suited for research and flexible production environments
because it can be easily reconfigured to change the deposited
material structure. A shared assembly that provides the source
gases for all the deposition chambers reduces the component count
and cost while improving the consistency of source gas delivery to
all the chambers. Such an assembly also allows expensive
components, such as the in-line purifiers and filters to be shared.
The system may also include a redundant station that is fully
configured with the source gases that can be used as a spare
station in the event that one of the stations fails. The redundant
station will allows completion of all the process steps on the
substrates presently loaded into the system. After the work in
process (WIP) has been cleared, the affected station can be
serviced. The transport system may include a means to bypass a
failed station. Many other known system architectural features used
to recover WIP when one of the stations fails can be implemented on
this system.
[0055] The gas input ports can include a gas distribution nozzle
which substantially prevents CVD gases from reacting until the CVD
gases reach the surfaces of the plurality of substrates. Such gas
distribution nozzle are configured to substantially prevent
reactions of process gases from occurring away from the surface of
the plurality of substrates in the deposition chambers 110 and 152,
thereby preventing reaction by-products from embedding into the
material deposited on the surfaces of the substrates being
processed.
[0056] Also, each of the plurality of enclosures 108 includes at
least one exhaust port to remove process gasses and reaction
by-product gasses. In one embodiment, a ring-shaped exhaust port
120 is used to remove the process gasses and reaction by-product
gasses. The at least one exhaust port 120 is coupled to an exhaust
manifold. A vacuum pump is coupled to the exhaust manifold. The
vacuum pump evacuates the exhaust manifold, thereby creating a
pressure differential which removes the process gases and reaction
by-product gasses from the plurality of deposition chambers 110 and
152. The exhaust ports are also configured to substantially prevent
reactions of process gases from occurring away from the surface of
the substrates in the deposition chambers 110 and 152, thereby
preventing contamination of the deposited film. Depending on the
gas load for each chamber, exhaust pumps can also be shared across
multiple chambers provided there is no cross talk and the gases
being exhausted are compatible with each other.
[0057] The transport mechanism 104 transports each of the plurality
of substrate carriers 114A and 114B to each of the plurality of
enclosures 108 in discrete steps that allow one or more processing
steps to be performed in each of the plurality of enclosures 108
for a predetermined time. There are numerous means for transporting
the plurality of substrate carriers 114A and 114B between the
plurality of deposition chambers 110 and 152 in discrete steps and
types of transport mechanisms according to the present teaching.
For example, one type of transport mechanism according to the
present teaching transports each of the plurality of substrate
carriers 114A and 114B to each of the plurality of enclosures 108
on along a rail. Another type of transport mechanism according to
the present teaching transports each of the plurality of substrate
carriers 114A and 114B to each of the plurality of enclosures 108
on a track. Another type of transport mechanism according to the
present teaching transports each of the plurality of substrate
carriers 114A and 114B to each of the plurality of enclosures 108
with a conveyor type transport mechanism which, for example, uses a
conveyor belt. In such transport systems, the rail, track, or
conveyor systems, which can also include belts, push-rods, and
magnetically coupled drives such as magnetic linear motors, can be
designed to provide electrical power to the plurality of heaters
122A and 122B. In addition, in such transport systems, gas for
pneumatically operated components, such as a rotation and/or
translation assembly for the substrate carriers 114A and 114B can
be provided from the rail, track, or conveyor systems.
[0058] The transport mechanism 104 shown in FIG. 1 moves the
substrate carriers 114A and 114B in a path from the first enclosure
to the second enclosure. In practice, there will typically be more
than two substrate carriers 114A and 114B and enclosures 108
forming more than two deposition chambers 110 and 152. In various
embodiments, the transport mechanism 104 can transport the
substrate carriers in a straight linear direction or in a curved
direction. The path that the transport mechanism transports the
plurality of substrate carriers 114A and 114B can be an open path
where the beginning and the end are at different physical locations
with a straight or curved path between the beginning and end
locations. Alternatively, the path that the transport mechanism 104
transports the plurality of substrate carriers 114A and 114B can be
a closed path where the end of the path returns to the beginning of
the path at a single location. In various embodiments, the closed
path can be a non-linear path, for example and not limited to, a
circular, oval, or a continuous track (for example, a tank tread)
shaped.
[0059] In many embodiments, the transport mechanism 104 transports
the substrate carriers 114A and 114B through the multi-chamber CVD
deposition system in one direction. However, in other embodiments,
the transport mechanism transports the substrate carriers 114A and
114B through the multi-chamber CVD deposition system in a first
direction and then back through the multi-chamber CVD deposition
system 100 in a second direction that is opposite to the first
direction.
[0060] In the embodiment shown in FIG. 1, there is one substrate
loading/unloading station 102 for inserting substrates into the
multi-chamber CVD system 100 for processing and another substrate
loading/unloading station 112 for removing processed substrates
from the multi-chamber CVD system 100 after processing. In
multi-chamber CVD systems 100 according to the present teaching
that include a closed path, there can be a single substrate
loading/unloading station that inserts substrates into the
multi-chamber CVD system 100 for processing and that removes the
processed substrates from the multi-chamber CVD system 100 after
processing. In many embodiments, the substrate handling from the
substrate loading/unloading stations 102, 112 is automated by
robotic transport mechanisms. The loading and unloading stations
can also function to either remove/add carriers from the system
either for servicing or cleaning depending on the process
requirements. For example, for MOCVD growth of As/P based
materials, the carrier can be reused multiple times before cleaning
is necessary, while cleaning after each deposition cycle is
necessary for growth of GaN based materials. In addition, there can
be one or more access stations or ports so that a user can access
the platen, or wafer carrier, for removal/replacement and/or any
other kind of adjustment.
[0061] Some multi-chamber CVD systems according to the present
teaching include a transport mechanism comprising heaters that are
positioned in close proximity to and integral with the substrate
carriers 114A and 114B so that they are in thermal communication
with the growth surfaces of the substrates. In such systems, the
heaters 122A and 122B move along with the substrate carriers 114A
and 114B. Power for resistive heaters that are integral with the
substrate carriers 114A and 114B can be provided by the transport
mechanism or can be provided by movable power cables.
[0062] In some systems according to the present teaching, at least
one of the plurality of enclosures comprises at least one in-situ
measurement device 124. In some systems, at least one of the
plurality of enclosures can include a pyrometer that measures the
temperature at the growth surfaces of the substrates positioned on
the plurality of substrate carriers 114A and 114B during
deposition. The resulting temperature measurement can be used to
provide feedback to the heater controls circuit in order to
maintain a desired growth temperature at the surface of the
substrates. Also, in some systems, at least one of the plurality of
enclosures 110 and 152 includes a reflectometer that measures
thickness and/or growth rate of the deposited films. The
reflectometer can provide a feedback signal that controls various
deposition parameters, such as the temperature at the growth
surface of the substrate, process gas flow rate, and pressure in
the deposition chambers 110 and 152. Additional in-situ measurement
devices 124 include other metrology tools commonly used in the
semiconductor industry, including, for example, a deflectometer,
which can be used for measuring curvature of a wafer during
deposition, ellipsometer, photoluminescence spectrometer,
reflectometer, combination pyrometer/reflectometer, a combined
deflectometer/reflectometer/temperature tool, and
electroluminescence spectrometer, and the like. The combination
pyrometer/reflectometer can be one as disclosed, for example, in
U.S. Pat. No. 6,349,270. The combined deflectometer, reflectometer,
and temperature tool is available as a DRT-210 in-situ process
monitor from Veeco Instruments.
[0063] FIG. 2A illustrates a side-view of one embodiment of a
deposition chamber 200 according to the present teaching where the
deposition chamber 200 is formed by moving an enclosure 202 over
the substrate carrier 204. In this embodiment, the substrate
carrier 204 is fixed in the vertical direction. For example, the
substrate carrier 204 can be attached to a track, rail, or a
conveyor-type transport system, which can also include belts,
push-rods, and magnetically coupled drives such as magnetic linear
motors, that transports the substrate carrier 204 (supported by
spindle 240) in the horizontal direction through the multi-chamber
deposition system 100 (FIG. 1). An actuator 206 translates the
enclosure 202 in the vertical direction over the substrate carrier
204 to form the deposition chamber 208. The enclosure 202
interfaces with the transport system 210 to form a seal that
contains the process chemistry in the deposition chamber 208. In
some systems, the transport system 210 includes a gas seal formed
on top of or into the top surface of the transport system 104. In
one specific embodiment, the transport system 210 is a
conveyor-type transport system that includes an o-ring type groove
formed into the top surface where the bottom edge of the enclosure
202 directly contact the o-ring type groove to compress an o-ring,
flange or gasket thereby forming a gas seal that substantially
contains the process gasses in the deposition chamber 208.
[0064] FIG. 2B illustrates a side-view of one embodiment of a
deposition chamber 250 according to the present teaching where the
deposition chamber 250 is formed by moving a substrate carrier 252
into an enclosure 254. In this embodiment, the enclosure 254 is
formed from non-movable front, back and side walls as well as a
ceiling defined by gas flow flange 300. Enclosures such as
enclosure 254 can be positioned at various locations within an
assembly area and they are fixed in both the vertical and the
horizontal directions so as to be plumb and level. An actuator 262
translates the substrate carrier 252 in a horizontal direction
until substrate carrier 252 is appropriately aligned under
enclosure 254. Then, actuator 256 moves substrate carrier 252 in a
vertical direction into the enclosure 254 to form the deposition
chamber 258. In some systems, the spindle 260 supporting the
substrate carrier 252 is moved in the vertical direction into the
enclosure 254 to form the deposition chamber 258. In these systems,
the transport system 262 can be is a fixed location. Also, in some
systems, the transport system 262 supporting the substrate carrier
252 is moved in the vertical direction so that the substrate
carrier 252 is positioned into the enclosure 254 to form the
deposition chamber 258. The enclosure 254 interfaces with the
transport system 260 to form a seal that contains the process
chemistry in the deposition chamber 258. The transport system 260
includes a gas seal, such as an o-ring, flange, or gasket seal
formed on top of or into the top surface of the transport system
260 that substantially contains the process gasses.
[0065] Referring again to FIG. 1, one skilled in the art will
appreciate that there are various other means for enclosing the
plurality of substrate carriers 114A and 114B and configurations
according to the present teaching where the plurality of enclosures
108 and the plurality of substrate carriers 114A and 114B interface
to form the plurality of deposition chambers 110 and 152. For
example, in one configuration, at least one of the plurality of
enclosures 108 and a corresponding one of the plurality of
substrate carriers 114A and 114B are both movable relative to each
other in order to form at least one of the plurality of deposition
chambers 110 and 152.
[0066] FIG. 4 shows a side-view of the embodiment shown in FIG. 1
where enclosures 108 are raised into recesses 170. In so doing, the
chambers 110 and 152 have been purged of reaction gases and the
pressure within house 106 has been equalized such that substrate
carriers 114A and 114B, together with their respective susceptor
116A and 116B, substrate carrier assembly 118A and 118B, spindles
140A and 140B, and in some cases heaters 122A and 122B, together
with heater supports 142A and 142B, can be moved by transport
mechanism 104 in housing 106 to the next step in the desired
process.
[0067] FIG. 5 illustrates a side-view of the embodiment of the
multi-chamber CVD system in FIG. 1 in another particular mode. The
side-view shows the substrate carrier 114B, together with its
respective susceptor 116B, substrate carrier assembly 118B, spindle
140B, and in some cases heater 122B, together with heater support
142B, have been moved from deposition chamber 152 into substrate
unloading station 112 and substrate carrier 114A, together with its
respective susceptor 116A, substrate carrier assembly 118A, spindle
140A, and in some cases heater 122A, together with heater support
142A, have been moved from deposition chamber 110 into deposition
chamber 152 for further processing.
[0068] FIG. 6 shows a side-view of an embodiment of the present
teaching where deposition chambers i, i+1, i+2, and i+3 have been
purged of process gases and the pressure within those areas have
been equilibrated. If desired, a gas curtain can be used between
deposition chambers i and i+1, i+1 and i+2, and i+2 and i+3 if
certain process conditions have to be maintained even though a
carrier(s) is being moved out of one of the chambers. The plurality
of substrate carriers 114i, 114i+1, and 114i+2, together with its
respective susceptors 116i, 116i+1, and 116i+2, substrate carrier
assemblies 118i, 118i+1, and 118i+2, spindles 140i, 140i+1, and
140i+2, and in some cases heaters 122i, 122i+1, and 122i+2,
together with heater supports 142i, 142i+1, and 142i+2, are in the
process from being moved by substrate transport mechanism 104 from
deposition chambers i, i+1, and i+2, respectively. In this
instance, enclosures 108i, 108i+1, 108i+2, and 108i+3 have been
raised into their respective recesses 170i, 170i+1, 170i+2, and
170i+3. Once the substrate carriers 114 are properly aligned within
its next deposition chamber; for example, substrate carrier 114i,
together with susceptor 116i, substrate carrier assembly 118i,
spindle 140i, and in some cases heater 122i, together with heater
support 142i in chamber i+1, substrate carrier 114i+1, together
with susceptor 116i+1, substrate carrier assembly 118i+1, spindle
140i+1, and in some cases heater 122i+1, together with heater
support 142i+1 in chamber i+2, and substrate carrier 114i+2,
together with susceptor 116i+2, substrate carrier assembly 118i+2,
spindle 140i+2, and in some cases heater 122i+2, together with
heater support 142i+2 in chamber i+3, enclosures 108i, 108i+1,
108i+2, and 108i+3 can be lowered out of recesses 170i, 170i+1,
170i+2, and 170i+3, to seal chambers i, i+1, i+2, and i+3 so that
the next deposition step in the desired process can be
performed.
[0069] Process gases used in CVD processing systems according to
the present teaching can be injected into the deposition chamber at
any angle relative to the substrate carrier. Some CVD processing
systems according to the present teaching inject the process gasses
in a vertical direction that is substantially perpendicular to the
surface of the substrate carrier. In these systems, the process
gasses can be injected via the gas flow flange 300 as discussed
herein. In other CVD process systems according to the present
teaching, the process gases are injected in a horizontal direction
where the gases flow in a direction that is substantially parallel
to the surface of the substrate carrier. For example, one
particular embodiments of the CVD processing system of the present
teaching uses the horizontal or parallel gas injection system as
depicted in FIGS. 7A and 7B.
[0070] FIG. 7A illustrates a side-view of one embodiment of a
deposition chamber 400 according to the present teaching where the
deposition chamber 400 is formed by moving an enclosure 402 over
the substrate carrier 304. In this embodiment, the substrate
carrier 304 is fixed in the vertical direction. For example, the
substrate carrier 304 can be attached to a track, rail, or a
conveyor-type transport system, which can also include belts,
push-rods, and magnetically coupled drives such as magnetic linear
motors, that transports the substrate carrier 304 (supported by
spindle 340) in the horizontal direction through the multi-chamber
deposition system 100 (FIG. 1). An actuator 406 translates the
enclosure 402 in the vertical direction over the substrate carrier
304 to form the deposition chamber 308. The enclosure 402
interfaces with the transport system 310 to form a seal that
contains the process chemistry in the deposition chamber 308. In
some systems, the transport system 310 includes a gas seal formed
on top of or into the top surface of the transport system 310. In
one specific embodiment, the transport system 310 is a
conveyor-type transport system that includes an o-ring type groove
formed into the top surface where the bottom edge of the enclosure
402 directly contact the o-ring type groove to compress an o-ring,
flange or gasket thereby forming a gas seal that substantially
contains the process gasses in the deposition chamber 308.
[0071] Plate 420 contains a sufficient number of horizontally
mounted tubes, for example tubes 412, 414, and 416 (not all tubes
are identified), which can be placed in at an appropriate distance
from the top of substrate carrier 308. Depending upon the
arrangement within the chamber 308, tubes 412, 414, and 416 can
each carry precursor gases or carrier gases, depending upon the
MOCVD process being conducted in the chamber 308. In many
instances, the tube carrying the inert gas will be placed between
the tube carrying the carrier gas and the tube carrying the
reactant gas. Holes or slits placed at the bottom of the tubes
which face the top surface of substrate carrier 304 allow for the
gases to flow towards the carrier 304.
[0072] FIG. 7B illustrates a top-down view (in the A direction as
shown in FIG. 7A) of the deposition chamber shown in FIG. 7A (with
many chamber parts removed). The top-down view of the deposition
chamber shows one embodiment of plate 420 having tubes 412, 414,
and 416. The arrows in the tubes 412, 414, and 416 show the general
direction of gas flow therein. Those skilled in the art will
appreciate that the directional flow of the gases can be changed
depending upon the particular CVD process being preformed. The
gases are discharged at an appropriate flow rate so that a desired
epitaxial structure is grown on the wafer as the substrate carrier
304 rotates. To increase uniformity of epitaxial structure growth
in the horizontal mode, the wafers would generally have to rotate
about their axis in a planetary motion, where the wafer carrier on
which the wafers are seated is rotated at a first rate while
rotating the wafers around themselves (within their wafer seat) at
a second rate, thereby creating planetary motion of the wafers in
the wafer carrier. Such systems have been suggested using planetary
gear systems, motor drivers rotating the wafer carrier and the
wafers placed thereon. Those skilled in the art will appreciate
that in certain circumstances, the substrate carrier 304 need not
rotate.
[0073] FIG. 8 illustrates a perspective top-view of another
variation of a horizontal flow gas injector CVD system 500
according to the present teaching. The horizontal flow gas injector
500 can be used instead of or to supplement the gas flow provided
by plate 420 and tubes 412, 414, and 416. The CVD system 500
includes circular gas injectors 504, 506, and 508 that inject
precursor gases and inert gases in the plane of the platen 510
(i.e. horizontal flow into the process chamber). The first circular
gas injector 504 is coupled to a first precursor gas source 512.
The second circular gas injector 506 is coupled to an inert gas
source 514. The third circular gas injector 508 is coupled to a
second precursor gas source 516. In some instances, the first and
third circular gas injectors 504, 508 are also coupled to a carrier
gas source. The first circular gas injector 504 injects the first
precursor gas in a first horizontal region 518. The third circular
gas injector 508 injects the second precursor gas in a second
horizontal region 520. A circular electrode 522 is positioned in
the first horizontal region 518 so that first precursor gas
molecules flow in contact with or proximate to the circular
electrode 522. A physical or chemical barrier can be positioned
between the first and the second horizontal regions 518, 520 in
order to isolate the circular electrode 522 from the flow of the
second precursor gas molecules.
[0074] In some instances, a baffle is positioned above the circular
electrode 522 to substantially prevent the first precursor gas
molecules from being thermally activated by the electrode 522 as
they flow to the platen 510. In some instances, a gas curtain is
used to separate the first and the second horizontal regions 518
and 520. In these systems, the second circular gas injector 506
injects inert gas between the first and the second horizontal
regions 518, 520 in a pattern that substantially prevents the
second precursor gas molecules from being activated by the circular
electrode 522.
[0075] Methods of operating the CVD system 500 include injecting
the first precursor gas with the first circular gas injectors 504
and injecting the second precursor gas with the third circular gas
injectors 508. An inert gas is injected between the first and the
second horizontal regions 518, 520 with the second circular gas
injectors 506 to form a chemical barrier that prevents the second
precursor gas molecules from being activated by the circular
electrode 522. When the circular electrode 522 is powered by a
power supply 220, the circular electrode 522 thermally activates
first precursor gas molecules injected by the first circular gas
injector 504 that flow in contact with or in close proximity to the
circular electrode 522. The activated first precursor gas molecules
and the second precursor gas molecules then flow over the surface
of the substrates 524, thereby reacting to form an epitaxial layer.
Purge gases can also be added as necessary (for example adjacent to
the enclosure, or below the carrier) to keep these regions clear of
parasitic deposition. Parasitic deposition can result in memory
effects, particulate contaminations, flow blockage, and hazardous
buildup, all of which are undesirable side-effects of CVD.
[0076] FIG. 9 illustrates a side-view of another variation of a
horizontal flow gas injector CVD system according to the present
teaching. Substrate carrier 182 includes a susceptor 186 and
substrate carrier assembly 184. The substrate carrier 182,
including susceptor 186 and substrate carrier assembly 184 are a
planetary type carrier as discussed above and is typically made of
a material having high thermal conductivity at high temperature so
that thermal energy is easily transferred from heater 192 to the
substrate. Spindle 140 supports susceptor 186 and spindle 140 is
connected to transport mechanism 104 as discussed above. Chamber
198 is formed by moving substrate carrier 184 into an enclosure
190, which is formed from non-movable front, back and side walls as
well as ceiling defined by a multi-zone showerhead 188. Enclosures
such as enclosure 190 can be positioned at various locations within
an assembly area and they are fixed in both the vertical and the
horizontal directions so as to be plumb and level.
[0077] Enclosure 190 is shown in formed position. Similar to the
embodiment disclosed in FIG. 2B, an actuator 104 translates the
substrate carrier 182 in a horizontal direction until substrate
carrier 182 is appropriately aligned under enclosure 190. Then, an
actuator (not shown) moves substrate carrier 182 in a vertical
direction into the enclosure 190 to form the deposition chamber
198. This system can also be moved in the additional manners as
discussed above regarding FIG. 2B. Appropriate seals are put into
place to prevent the leakage of process gases.
[0078] As part of this system, two different arrangements of
process gases are shown and those skilled in the art will
appreciate that there are many other arrangements for introducing
the process gases into the chamber 198 in a horizontal fashion.
Process gases can enter the chamber from arrangement 194, which
contains three gases A, B, and C, at injectors 222. Exhaust 180 is
located centrally over chamber 198 and is heated so as to prevent
or reduce gas phase nucleation and helps avoid gas flow stagnation
within the chamber. Process gases can also enter the chamber from
arrangement 196, which contains three gases D, E, and F, at
injectors 224. Injectors 222 or 224 are three zone peripheral type
injectors which can provide controlled pre-mixing of the process
gases, pre-heating of ammonia and other inert gases, and provide
for radial flow of the gases from the chamber walls to the center
of the chamber.
[0079] In some systems, it may be advantageous to have one
precursor or carrier gas injected in a substantially perpendicular
direction to the carrier surface and another precursor or carrier
gas injected in a substantially parallel direction to the carrier
surface.
[0080] One feature of the multi-chamber deposition system of the
present teaching is that it can have very high throughput and,
therefore, it is particularly suitable for mass production
applications. High throughput can be obtained because each of the
plurality of deposition chambers can be optimized for growing a
particular layer structure to a particular thickness. In
embodiments where the heaters 122A and 122B are fixed inside or
proximate to the deposition chambers 110 and 152, the heaters 122A
and 122B can be operated in a narrow temperature range that heats
the growth surfaces of the substrates to their desired
temperatures. In such systems, the time that it takes the growth
surfaces to reach their desired growth temperatures can be
minimized.
[0081] Another feature of the multi-chamber deposition system of
the present teaching is that it is easily reconfigured to deposit
different material layer structures and, there it is also very
suitable for research and test environments. Another feature of the
multi-chamber deposition system of the present teaching is that the
system is highly repeatable because each of the substrates is
exposed to substantially the same process conditions. The intrinsic
process stability for each chamber is improved since each chamber
is assigned to a subset of the process steps. Cross talk and memory
effects, which can arise when disparate process steps sensitive to
residual gas contamination from a prior step are performed in the
same chamber, can be essentially avoided in the in-line
architecture of the present teaching.
[0082] Yet another feature of the multi-chamber deposition system
of the present teaching is that the system can be easily configured
to perform in-situ characterization of the layers deposited on the
substrates in the plurality of deposition chambers 110 and 152. One
skilled in the art will appreciate that numerous types of in-situ
measurement devices can be used to characterize the deposited films
in the plurality of deposition chambers 110 or between the
plurality of deposition chambers 110 and 152. Measurements may also
be performed as substrates are transiting across multiple chambers
by including a short section that includes in-situ measurement
devices.
[0083] In general, a method of forming multiple epitaxial layers on
a substrate using a multi-chamber chemical vapor deposition system
according the present teaching includes enclosing a first rotatable
substrate carrier comprising at least one substrate at a first
location to form a first deposition chamber that maintains a first
independent environment, which can be a chemical vapor deposition
process chemistry environment. The enclosing the first substrate
carrier to form the first deposition chamber can include moving an
enclosure over the first substrate carrier to isolate the first
chemical vapor deposition process chemistry inside the first
deposition chambers. The enclosing the first substrate carrier to
form the first deposition chamber can also include moving the first
substrate carrier into an enclosure or chamber to isolate the first
chemical vapor deposition process chemistry inside the first
deposition chambers. Alternatively, the enclosing the first
substrate carrier to form the first deposition chambers can include
forming gas curtains to isolate the first chemical vapor deposition
process chemistry.
[0084] A first epitaxial layer is grown on the at least one
substrate in the first deposition chamber at the first location
with the first independent chemical vapor deposition process
chemistry. Any means for growing the first epitaxial layer on the
at least one substrate can be used. A heater positioned inside or
outside of the first deposition chamber is used to heat the growth
surface of the at least one substrate. At least one CVD process gas
is provided to the first deposition chamber at a flow rate that
results in the deposition of a desired film by chemical vapor
deposition. The at least one CVD process gas can be at least one
MOCVD gas.
[0085] The first substrate carrier is transported after the first
epitaxial layer is grown to a second location. In some methods, the
heater associated with the first substrate carrier is transported
along with the first substrate carrier. The first substrate carrier
can be transported by numerous means such as by transportation
along a track, rail, or a conveyor-type mechanism, which can also
include belts, push-rods, and magnetically coupled drives such as
magnetic linear motors. The first substrate carrier is then
enclosed to form a second deposition chamber that maintains a
second independent chemical vapor deposition process chemistry.
[0086] A second epitaxial layer is grown on top of the first
epitaxial layer in the second deposition chamber at the second
location with the second independent chemical vapor deposition
process chemistry. Any means for growing the second epitaxial layer
on the at least one substrate can be used. A heater positioned
inside or outside of the second deposition chamber is used to heat
the growth surface of the at least one substrate and CVD process
gasses.
[0087] It is also possible to deposit multiple epitaxial layers, or
a stack of layers, within each transport sequence, that is, in each
chamber before the substrate carrier (loaded with substrates) is
moved from one chamber to another chamber.
[0088] At least one CVD process gas is provided to the second
deposition chamber at a flow rate that results in the deposition of
a desired film by chemical vapor deposition. The at least one CVD
process gas can be at least one MOCVD gas. The method can include
configuring a gas distribution manifold to provide the desired CVD
gases to each of the first and the second deposition chambers.
[0089] The method of forming multiple epitaxial layers on the
substrate using the multi-chamber chemical vapor deposition system
continues with a second rotatable substrate carrier. The second
rotatable substrate carrier comprising at least one substrate at
the first location is enclosed to form the first deposition chamber
that maintains the first independent chemical vapor deposition
process chemistry. The first epitaxial layer is then grown on
substrates positioned on the second substrate carrier in the first
deposition chamber at the first location with the first independent
chemical vapor deposition process chemistry. The at least one
substrate on the first and the second substrate carriers are
typically processed simultaneously in time.
[0090] The method continues with the first substrate carrier being
transported after the second epitaxial layer is grown to a third
location. The first rotatable substrate carrier comprising at least
one substrate is then enclosed at a third location to form a third
deposition chamber that maintains a third independent chemical
vapor deposition process chemistry. In some methods, the heater
associated with the third substrate carrier is transported along
with the third substrate carrier. The second rotatable substrate
carrier is transported to the second location where it is enclosed
to form the second deposition chamber that maintains the second
independent chemical vapor deposition process chemistry. A third
rotatable substrate carrier is transported to the first location
where it is enclosed to form the first deposition chamber that
maintains the first independent chemical vapor deposition process
chemistry. The transporting of the first, second, and third
substrate carriers can be performed simultaneously. In addition,
deposition can be performed in the first, second, and third
deposition chambers simultaneously. This method is continued for a
forth and additions substrate carriers. As discussed before, not
all chambers may be similar or used for CVD processes. Some
chambers may be devoted exclusively to baking/heat up of the
carrier, annealing prior to or following a process step, cool-down
at the end of the process sequence or a surface modification step
prior to or following a process step.
[0091] In other methods and systems according to the present
teaching, the substrate carrier is not a rotatable carrier. Those
skilled in the art will appreciate how to deposit and grow
epitaxial layers in such systems or by such methods in accordance
with the present teachings set forth hereinabove.
[0092] In some methods according to the present teaching, in-situ
measurements of deposited material layers properties are performed
during deposition. For example, in-situ pyrometry can be performed
while growing at least one of the first and second epitaxial layers
to monitor the growth temperate at the surface of the substrates.
In addition, in-situ reflectometer can be preformed to measure film
thickness and/or growth rate of the deposited films.
Equivalents
[0093] While the applicant's teaching are described in conjunction
with various embodiments, it is not intended that the applicant's
teaching be limited to such embodiments. On the contrary, the
applicant's teaching encompass various alternatives, modifications,
and equivalents, as will be appreciated by those of skill in the
art, which may be made therein without departing from the spirit
and scope of the teaching.
* * * * *